Routine application of partial zona dissection for male factor infertility

Abstract

Partial zona dissection (PZD) increases the chances of fertilization by improving the access of spermatozoa to the perivitelline space (PVS) helping those spermatozoa unable to penetrate the zona pellucida (ZP) and possibly those poorly able to penetrate the oolemma. Problems arise in assessing semen to decide which parameters might indicate defects of this nature. PZD, by circumventing the ZP, may also increase the rate of polyspermy, especially in infertility where ZP and oolemmal penetration are not defective. Given these drawbacks, we performed PZD as routine treatment for male infertility in 70 in-vitro fertilization cycles. In three different groups, PZD proved to be either effective, ineffective or unnecessary. In the first group of 35 cycles, fertilization was 23% with initial PZD and 33% with PZD reinsemination (36% and 41% polyspermy respectively). No fertilization occurred following conventional insemination (CONV). Four pregnancies occurred in this group. In a second group of 19 cycles, fertilization did not occur with either PZD or CONV. In the final group of 16 cycles, fertilization was similar following both PZD and CONV, but polyspermy was 48% in the PZD category. Transfer of mixed PZD and CONV embryos in this group yielded 10 pregnancies. Assessment of all patient and seminal profiles, and those in an oligozoospermic subcategory, revealed no parameters of relevance to success or failure with PZD. However, one subgroup in the group of total failure to fertilize did have a significantly lower percentage of normal morphology (P less than 0.005), suggesting that degree of teratozoospermia may be a prognosticator of success using PZD.